Automatic blank-feeding apparatus.



PATENTED JUNE 27, 1905.

J. H. MOELROY.

AUTOMATIC BLANK FEEDING APPARATUS.

APPLICATION FILED AUG. 27, 1903.

3 SHEETS-SHEET l.

PATENTED JUNE 27, 1905.

J. H. MOELROY.

AUTOMATIC BLANK FEEDING APPARATUS.

APPLICATION FILED AUG. 27, 1903.

3 SHEETS-SHEET 2.

PATENTED JUNE 27, 1905.

J. H. MOELROY.

AUTOMATIC BLANK FEEDING APPARATUS.

APPLIOATION FILED AUG.27, 1903.

3 SHEETS-SHEET 3.

Patented June 27, 1905.

PATENT FFICE.

JOHN IIOIVARI) MoICLltOY, OF CHICAGO, ILLINOIS.

AUTOMATIC BLANK-FEEDING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 793,212, dated June 27,1905.

Application filed August 27,1903. Serial No. 170.955.

.To 1/ 117mm if HHII'I/ (o/merit:

Be it known that I, Joux IImvium McEnnoY, a resident of Chicago, in thecounty of Cook and State of Illinois, have invented certain new anduseful Improvements in Automatic Blank-Feeding Apparatus, of which thefollowing is a specification.

Hy invention is concerned with certain new and useful improvements inautomatic blankfeeding mechanism which I have devised primarily forfeeding the blanks to a can-body machine, but which may be employed forany similar purpose.

I will first describe the mechanism in which I have embodied myinvention and finally in the claims pointout what I consider to be thenovel features thereof.

To illustrate my invention, I annex hereto three sheets of drawings, inwhich the same reference characters are used to designate identicalparts in all the figures, of which Figure l is a side elevation of myinvention as applied to a can-body lock-seamer of any reciprocating-feed type. Fig. 2 is a front elevation of the same. Fig. 3 isa central longitudinal section. Fig. 4: is a top plan view.

Fig. 5 is a sectional view on the line A A of Fig. I. Fig. (i is adetail illustrating a medllication. Fig. I is a diagrammatic view of theelectrical connections employed in connection with the form previouslyillustrated. Fig. 8 is a detail showing the contacts. Fig. E) is adiagrammatic view similar to Fig. T, but illustrating a modification;and Fig. 11) is a diagrammatic view illustrating a modification and theelectrical circuits employed in connection with apparatus forcontrolling the operation thereof.

In carrying out my invention I employ a pair of frame-pieces 11, whichare suitably secured on the framework 12 of the machine with which themechanism is employed. A transverse piece 12) connects the side piecesand serves as a support upon which the corner-pieces II are adjustablysecured in order that the apparatus may be adjusted for different-sizedblanks. The two corner-pieces ll, together with the front piece 15,which is pivotally mounted on the rod 16, connecting the two side pieces11, form the blank-holder.

The front piece 15 is held rigidly in a vertical position by the bar 16cooperating with apertures 17 in the frame-pieces, and by removing thebar 16 the front piece 15 can be swung down to insert a fresh supplyofblanks. The blanks are supported upon the verticallymovable table 18,which is secured to one or more rack-bars 19, which are raised slowly bythe gear-wheels 20, secured on the shaft 21, journaled in suitablebearings in the side pieces 11. The roller 22, also journaled in theside pieces, serves to hold the rack-bar in engagement with thegear-wheels. To rotate the shaft 21 at the proper rate of speed to keepthe blanks 23 at the proper level as they are carried away one by one, Iemploy the lever 2 t, which is swung at certain distance at eachoperation by the cam 25, secured on the shaft 26, which is operated bymechanism to be subsequently described. A pawl .27 on the lever 24engages the teeth of a ratchet-wheel 28 to advance the same one or morenotches at each rotation of the shaft 26. A detentpawl 23) holds theratchet-wheel in its advanced position.

A pair of angular guiding and supporting pieces 30, supported from themain machine, extends out over the blank-holder, the horizontal flangesbeing cut away just over the holder to permit a blank to be raisedwithout interfering therewith. The blanks are fed forward by thereciprocation of the bars 31, extending from the main machine andprovided with the yielding spring-pressed pawls 32, which advance theblanks forward step by step, as is customary in this class of devices.To raise the blanks, I employ adhering lifters 33, which are seen redupon the bar 3t, extending across the top of the blank-holder and veryloosely pivoted by the ears upon the pair of arms 36, which is pivotedat 37 on stub-shafts supported by the side pieces 11. To raise and lowerthe arms 36, and thereby the lifters 33, at each operation of themachine, .I journal in the side pieces 11 a shaft 26. previouslyreferred to, which has a pair of cams on its ends in the proper plane tocooperate with the arms 36, preferably through the medium of theantifriction-rollers 39, mounted on said arms above the U- LOG shapedrecesses 40, formed therein, to permit the arms 36 to be lowered withoutinterfering with the shaft 26. Rigidly secured to the cross-piece 34,preferably by the arm 41, by which it is loosely fulcrumed at one end,is the arm 42, the outer end of which is screwthreaded and provided withthe weight 43, which can be secured thereon in any desired position ofadjustment to cause the arm 42 and its weight to counterbalance theweight of the cross-piece 34, the lifters 33, and the blank 23. Thisweight is so adjusted that if the lifters carry up a single blank theywill not be overweighted and the arm 42 will remain resting on the shaft26. If on account of the adhesion of the blanks two or more are liftedsimultaneously, they will overbalance the arm 42 and weight 43, and asthe parts are raised the lifters will swing down relatively to the arms36, and this swinging movement is utilized to release the blanks beforethe carrier-bars 31 can pass beneath them, and thus carry more than asingle blank to the machine. If the lifter is pneumatic, as illustratedin Fig. 6, where 33 is the customary pneumaticlifter, the release of theadhesion may be effected by having the valvestem 44 extend over a rod45, connecting the outer ends of the arms 36. From a consideration ofthis construction it will be apparent that if the front end of thebalance is overweighted by the adhesion of more than one blank as thearms 36 are raised the bar 34 swinging down relative to the arms 36 willcause the valves 44 to be lifted and the adhesion of the lifterreleased.

The features of my invention which have hitherto been described may beemployed in connection with any kind of a lifter, such as any kind of asuction device or a permanent magnet; but I prefer to employelectromagnets as lifters and energize them at each .operation of themachine, preferably by closing the circuit in which they are included.

The electromagnets 33 are of any desired construction, but preferablyhave their cores made of Swedish iron, which demagnetizes quickly toallow the blanks to drop when the circuit is broken with the parts inthe position shown in Fig. 3. To prevent any failure of thedemagnetization, I preferably employ in connection therewith hammers'46,which are carried by the frame 47, pivoted at 37 and having thecross-piece 48, which engages with the cam 49, secured on the shaft 26.This cam raises the hammer gradually, but allows it to fall veryabruptly, the effect of gravity being increased, if desired, by thecoiled springs 50, cooperating with the frame 47 and put under tensionas it is raised. The striking of the cores of the electromagnets bythese hammers serves to release the blanks certainly not only by thedemagnetization, but also by the ordinary physical jar, the latterfeature of which might be employed in connection with permanent magnets.

To prevent the blanks which have been advanced by the pawls 32 frombeing carried back by friction therewith, I may employ, in connectionwith each space, one or more electromagnets 51, which may be continuallyenergized, but which are preferably in circuit with the magnets 33, sothat they are energized only while the bars 31 are moving outward toreceive fresh blanks. The lift of these magnets 51 may be adjusted so asto simply overcome the effect of friction, or it may be adjusted so thatthe blanks will be raised entirely off of the bars 31. These magnets 51are conveniently supported from crosspieces 52, which are held inposition upon the brackets 53, extending up from the angleirons 30. Topermit the movement of the angle-irons, the cross-pieces 52 areconnected therewith by pin-and-slot connections, as shown at 53. I

In the preferred form of my invention, which is illustrated moreespecially in Fig. 10, instead of employing ordinary electromagnets Iemploy solenoids 33", with the cores loose therein and adapted to dropdown on the blanks, while the coils remain stationary, being supportedby across-piece 34", suitably supported from the side pieces. I arrangethe circuit so that it is broken just as the bars 31 reach theiroutermost position,

and the blank 23, with its'attached cores, drops I onto the bars 31 inadvance of the hooks by which the blanks are carried away from thecores, which then drop the remaining distance and rest upon theuppermost blank. As soon as the bars 31 are drawn from over the pile ofblanks the circuit is closed, and the pull of the solenoid lifts thecores and the attached blank above the plane of the top of the bars31,thus dispensing with the mechanism shown in Figs. 1 to 4 for liftingthe magnets with the attached blanks. To insure the lifting up of theblank with the cores, I may insert in the center of the soft-iron core asmall permanent bar-magnet, which will always adhere to the blank, butnot with sufficient force to seriously resist the action of the bars 31in pulling it loose. The strength of the current in this form isadjusted so that the lifting force of the solenoids will be justsuflicient to carry up a single blank; but if more than one blankadheres the strength of the current will not be sufficient to lift them,and they will stay down, this electric balance, as it were, taking theplace of the physical balance shown in Figs. 1 to 6. A simplearrangement of the circuit for this and the other form is shown in Fig.7, where the solenoid-wire 33 is in circuit with a resistance 54, bywhich the exact amount of current necessary to secure the balancedescribed can be applied, an ammeter 55 being included in the circuit,so that in case the current should become reduced the attendant can knowwhen a sullicient amount of resistance has been thrown out, the exactcurrent necessary to the proper operation being of course known to theattendant. To make and break the circuit at each rotation of the shaft26, I secure on the under side of the bar t2 two separated contacts 56,which rest on a disk 57, secured on the shaft 26, half of which isinsulated, so that the circuit will be closed during half of therotation of the shaft and opened the other half. in case theconstruction shown in Figs. 1 to 5 is employed the tilting of the armat! will raise the contacts 56 off of the disk 57 and break the circuitin case two or more blanks are lifted. A modilicatitm of thisconstruction is indicated in Fig. 9, where instead-of breaking thecircuit in case it is overbalanced I employ an additional contact 58,which slides over an additional resistance 59, so as to automaticallydecrease the lifting power by thus throwing in additional resistance incase more than one blank is lifted. \Vith this modification the contacts56 will have to cot'iperate with a segmental plate 57, so as to permit aconsiderable movement of the arm 42 without breaking the circuit at thatpoint.

Referring now to Fig. 10, I have therein illustrated certain additionalmechanism by which the operation of the feed apparatus is controlledunder certain contingencies. \Yith this construction the solenoid-lifter3?), with the movable cores, is employed, and the connections of thecircuit (l, in which it is included, are substantially the same as thoseshown in Fig. 7, except that the arm i2 is omitted, as the electricalbalance is en'iployed. In case the apparatus by which the blanks arekept at a certain level does not work satisfactorily I employ mechanismand alarms to either correct the difliculty or call the attendantsattention, so that he may correct it in case no automatic mechanism forcorrect;- ing it is employed. If the mechanism should feed too rapidlyand the supply of blanksbecome too high, I employ two contacts (it) and(31, which terminate in position so that if the blanks are at the properlevel they are just below or possibly on a level with the contact 61),which is separated from the contact at by a space of more than thethickness of a sheet of tin, so that the circuit is not closed as asingle sheet of tin is lifted. It will be apparcut that I might usethese contacts for breaking the main circuit if two or more sheets oftin were lifted by separating the contacts sufliciently so that theywould not be closed by the passage of one sheet, but would be closed bythe passage of two or more. In the present construction, however, Iarrange to have the contacts closed when the pile gets high enough tobegin to interfere with the movement of the bars 31. These contacts (it)and 61. are an electrical circuit c, which includes a solenoid 62,carried by the lever 2st and having its core 63 secured to the pawl 27,so that when the circuit is closed the pawl is lifted out of engagementwith the teeth of the wheel 28, and the upward feeding of the blanksceases until the pile is lowered sulliciently to break the circuit, whenthe spring 64; or gravity carries the pawl 27 back into engagement withthe wheel 28 and the feeding of the blanks is resumed. This circuit alsoincludes an alarm (55, which begins to ring and calls the attentionofthe attendant to the fact that the blanks are above the normal level,which may be produced by a failure of the feeding mechanism to carrythem off, so that he can remedy the dilliculty. If, on the other hand,the supply of blanks should fall too low, 1 employ a contact 66, whichis insulated from the pile of blanks and which has a pivoted contact (37cooperating therewith and held out of engagement therewith by the blankswhen they are above or at the proper level. \Vheu they get too low, thecontact (37 falls on (it; and the circuit closed through the alarmbell(35, but not the solenoid 62, so that the attention of the attendant iscalled, but the op eration of the blank-supply mechanism is not stopped.

It is desirable to employ an alarm-bell by which the attendautcan beadvised of the fact that the supply of blanks is nearly exhausted by theplate to nearing the upward limit of its movement, and in case theattendant does not respond before the supply is entirely exhausted it isdesirable to have the machine automatically stopped. 'lo ellect thisresult, I employ another circuit 0, in which is a contact (38, carriedby the bottom of the plate 18, and coi'iperating therewith is a contact69, which is held in engagement therewith by a spring, provided thenumber of blanks resting on the top of the vertical rod 71), slidingthrough the plate 18, is small. If the weight of the blanks is great,the contacts will beheld apart. \Yhen the supply of blanks isstilliciently reduced, the circuit is closed and the alarm-bell 71,which is preferably of a dillerent tone from (35, so that the attendantmay distinguish between them, is rung. If the attendant does notreplenish the supply in time, when the last blank is removed thecontaetTQ, which is similar to (59, but weaker, so that it will be heldaway from the contact 68 by a single blank, is closed, and the solenoidT3 in this circuit is energized and its core H, which is connected tothe beltshifting lever 75, is pulled in and the belt 76 is thrown fromthe driving-pulley T7 to the idle pulley 7S and the machine is stopped.It will be apparent that the effect of closing the circuit whenthesupply is reduced or entirely exhausted might be effected by contactsproperly positioned to be closed by the advance of the plate 18 to acertain specilic point, thus dispensing with the spring mechanism shown.

IVhile I have shown and described my invention as embodied in the formswhich I at present consider best adapted to carry out its purposes, itwill be understood that itis capable of some modifications and that I donot desire to be limited in the interpretation of the following claimsexcept as may be necessitated by the state of the prior art.

That I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. In a blank-feeding apparatus, the combination with the blank-holder,of means for raising the blanks therein, means for carrying away theblanks one by one as they are separated, a driving-shaft, avertically-movable support, lifters carried by said support, a cam onthe driving-shaft, and a lever cooperating with the cam and engaging thesupport to raise the lifters at each operation of the machine toseparate a blank from the pile beneath.

2. In a device of the class described, the combination with theblank-holder, of means for raising the blanks therein, means forcarrying away the blanks one by one as they are separated, adriving-shaft, a vertically-movable support, lifters carried by saidsupport, a pair of cams located near the ends of the driving-shaft, apair of levers having lugs thereon engaging with the cams, andconnections between said levers and support so that both ends of saidsupport will be raised uniformly to operate the lifters.

3. In a device of the class described, the combination with theblank-holder, of the electromagnetic separator, an electric circuit inwhich the separator is included, a rotating shaft, two circuit-terminalsadjacent thereto, and a circuit-closing support carried by said shaftand closing the circuit through said terminals at each rotation.

4. In a device of the class described, the combination with theblank-holder, of the electromagnetic solenoid, the core adapted to reston the blanks, an electric circuit including the solenoid, means forenergizing the solenoid at regular intervals to lift the core andattached blank, and a member adapted to carry away the lifted blanks oneby one.

5. In a device of the class described, the combination with theblank-holder, of the electromagnetic separator, means for energizingsaid separator at regular intervals, and mechanism for striking the coreof said separator after the energization has ceased.

6. In a device of the class described, the combination with theblank-holder, of the magnetic separator, and means for striking saidseparator a sharp blow to insure the release of the blank. V

7. In a device of the class described, the combination with theblank-holder, of the electromagnetic solenoid, the core adapted to reston the blanks and having a permanent magnet carried thereby, an electriccircuit including the solenoid, means for energizing the solenoid atregular intervals to lift the core and attached blank, and a memberadapted to carry away the lifted blanks one by one.

8. In a device of the class described, the combination with theblank-holder, of the electromagnetic separator, an electric circuit inwhich the separator is included, means for breaking the circuit atregular intervals, and mechanism for automatically breaking the circuitas the separator advances if it carries more than one blank.

9. In a device of the class described, the combination with theblank-holder, of the electromagnetic separator, an electric circuit inwhich the separator is included, means for breaking the circuit atregular intervals, and mechanism for automatically breaking the circuitas the separator advances if it carries more than one blank, consistingof a balance mechanism adapted to be over weighted by extra blanks. 10.In a device of the class described, the combination with theblank-holder, of the separator, and a balance mechanism cooperatingtherewith to release any extra blanks.

11. In a device of the class described, the combination with theblank-holder, of the separator, a balance mechanism upon which it ismounted, and means for releasing the attraction of the separator if thebalance is destroyed.

12. In a device of the class described, the combination with theblank-holder, of the separator, an adjustable balance mechanism uponwhich it is mounted, and means for releasing the attraction of theseparator if the balance is destroyed.

13. In a device of the class described, the combination with theblank-holder, of the electromagnetic separator, an electric circuit inwhich the separator is included, means for breaking the circuit atregular intervals,mechanism for automatically breaking the circuit asthe separator advances if it carries more than one blank, said mechanismconsisting of a balance adapted to be overweighted by eX- tra blanks.

1 1. In a device of the class described, the combination with theblank-holder, of the electromagnetic separator, means for energizingsaid separator at regular intervals, and means for automaticallydiminishing the current if the separator carries more than a singleblank.

15. In a device of the class described, the combination with theblank-holder, of the electromagnetic separator, means for energizingsaid separator at regular intervals, and means for automaticallydiminishing the current if the separator carries more than a singleblank, said means consisting of a balance mechanism cooperating withresistance to increase the resistance as the balance is destroyed.

16. In a device of the class described, the combination with theblank-holder, of a verticaIly-reciprocating frame, a balance pivoted insaid frame, an adhering lifter carried by said balance, and means forautomatically destroying the adhesion of the lifter if the weight of theblanks adhering thereto is too great.

17. In a device of the class described, the combination with theblank-holder, of the electromagnetic separator, means for energizingsaid separator at regular intervals, and means for striking the core ofsaid separatmafter the energization has ceased, said means consisting ofa pivoted hammer and a rotating cam to raise it and allow it to descendabruptly.

18. In a device of the class described, the combination with thereciprocating carrier having the dogs to advance the blanks, of themagnets to prevent the return of the blanks with the carrier.

1f). In a device of the class described, the combination with thereciprocating carrier having the dogs to advance the blanks, of theeleetromagnets to prevent the return of the blanks with the carrier, andmeans for breaking the circuit while the carrier moves forward.

20. In a device of the class described, the combination with theblank'holder, of means for separating the blanks one by one, means forcarrying away the blanks, the verticallymoving support upon which theblanks rest, the rack-bar connected to said support, a shaft, a pinionon said shaft engaging the rack-bar, a ratchet-wheel on said shaft, anoperating-lever for the ratchet-wheel, a pawl carried by theoperating-lever engaging the ratchet-wheel, a stop-pawl also engagingthe ratchet-wheel, and a driving-shaft having a cam thereon serving tooperate the pawl-carrying lever.

21. In a device of the class described, the combinationwiththeblank-holder, of the electromagnetic separator, an electriccircuit in which the separator is included. an adjustable resistance inthe circuit by which the magnetic force may be regulated, and means forbreaking the circuit at regular intervals.

In a device of the class described, the cmnbination withtheblank-holder, of the vertically-movable support adapted to raise theblanks in said holder, arack-barconnected to said support, a shaft, apinion on said shaft, a ratchet-wheel on said shaft, an operating-leverfor the ratchet-wheel, a pawl engaging the ratchet and carried by thelover, a stoppawl also engaging the ratchet, a drivingshaft, alifter-support, lifters carried by said support, a lever coi'iperatingwith the liftersupport, and cams on the driving-shaft adapted to swingthe levers and raise the lifters and actuate the. rack-bar;substantially as and for the purpose described.

23. The combination with the blank-holder, of means for raisingtheblankstherein, means for carrying away the blanks one by one as they areseparated, a driving-sl aft, a vertically-moving lifter-simport, lifterscarried by said support, a cam on the driving-shaft, a levercotiperating with the cam and engaging the lifter-support, and means forcontrolling the rate of raising the blanks therein.

271:. In a device of the class described, the combination with themachine, of the loose and driving pulleys thereon, a belt-shifter, theautomatic blank-feed apparatus therefor, and means set in motion by theremoval of the last blank for moving the belt-shifter, said meansconsisting of an open circuitclosed by the removal of the last blank,and an electromagnet in said circuit acting on the beltshifter.

25. In a device of the class described, the combination with themachine, of the loose and driving pulleys thereon, a belt-shifter, theautomatic blank-feed apparatus therefor, and mians set in motion by theremoval of the last blank for moving the. belt-shifter, said meansconsisting of an open circuit closed by the removal of the last blank,and an electromagnet in said circuit acting on the beltshifter through aswinging lever terminating in a yoke en'ibracing the belt and a curvedsolenoid-core on the other end cooperating with said electromagnet.

26. In a device of the class described, the combination with themachine, of the automatic blankfeed apparatus therefor, and means forsounding an alarm when the blanksupply is about exhausted.

27. In a device of the class described, the combination with themachine, of the automatic blaukfeed apparatus therefor, and means forsounding an alarm when the blanksupply is about exhausted, consisting ofa circuit containing an alarm and spring-contacts held apart byacertainweight of blanks.

28. In a device of the class described, the combination with themachine, of the automatic blank-feed apparatus therefor, means forsounding an alarm when theblank-supply is about exhausted, and means forautomatically stopping the machine when the blanks are entirelyexhausted.

29. In a device of the class described, the combination with themachine, of the automatic blank-feed apparatus therefor, an electriccircuit containing an alarm and an elec tromagnet, and two sets of opencontacts in said circuit, one set being closed when the supplyof blanksis nearly exhausted and serving to ring the alarm, and the other setbeing closed by the removal of the last blank and serving to utilize theelectromagnet to set in motion mechanism to stop the machine.

30. In a device of the class described, the combination with operatingmechanism for keeping the supply of blanks at a certain level, saidmechanism including a ratchetwheel and a swinging actuating-pawl, ofmeans for stopping the operation of said mechanism if the supply exceedsa certain level, consisting of an electromagnet adapted to attract thepawl and carry it from engagen'ient with the ratchet- Wheel when thecircuit is closed by the position of the blanks.

81. In a device of the class described, the combination with operatingmechanism for keeping the supply of blanks at a certain level, of meansfor stopping the operation of said mechanism and sounding an alarm ifthe supply exceeds a certain level.

32. In a device of the class described, the combination with operatingmechanism for keeping the supply of blanks at a certain level, of meansfor stopping the operation of said mechanism and sounding an alarm ifthe supply exceeds a certain level, including an electric circuit whoseclosing is controlled by the position of the blanks.

33. In a device of the class described, the combination with operatingmechanism for keeping the supply of blanks at a certain level, of meansfor stopping the operation of said mechanism and sounding an alarm itthe supply exceeds a certain level, until said supply has reached itsnormal level.

34. In a device of the class described, the combination with operatingmechanism for keeping the supply of blanks at a certain level, of meansfor stopping the operation of said mechanism and sounding an alarm ifthe supply exceeds a certain level, until said supply has reached itsnormal level, said means including an electric current whose closing iscontrolled by the position of the blanks.

35. In a device of the class described, the combination with operatingmechanism for keeping the supply of blanks at a certain level, of meansfor sounding an alarm if the supply falls below a certain level.

36. In a device of the class described, the

combination with operating mechanism for keeping the supply of blanks ata certain level, of delivery mechanism for carrying the blanks away fromsaid supply one by one, and means for sounding an alarm if the operatingmech-' anism ceases.

37. In a device of the class described, the combination With operatingmechanism for keeping the supply of blanks at a certain level, of meansfor stopping the operation of said mechanism if the supply exceeds acertain level and for sounding an alarm if the supply falls below acertain level.

38. In a device of the class described, the combination with operatingmechanism for keeping the supply of blanks at a certain level, of meansfor sounding an alarm if the supply falls below a certain level and forsounding an alarm and stopping the operation of said mechanism if thesupply exceeds a certain level.

39. In a device of the class described, the combination with operatingmechanism for keeping the supply of blanks at a certain level, of meansfor-sounding an alarm if the supply falls below a certain level, saidmeans consisting of an open circuit containing an alarm, and contactsheld apart by the blanks when they are above a certain level.

L0. In a device of the class described, the combination with operatingmechanism for keeping the supply of blanks at a certain level, ofcontrolling mechanism connected therewith and including an open electriccircuit having contacts adjacent to the normal level and separated by agreater distance than the thickness of the blank.

JOHN HOWARD MOELROY.

W'itnesses:

S. E. HIBBEN, H. G. BARRETT.

